Wimpy

WIMPY sets your wimpy value. When your character takes damage that reduces
your hit points below your wimpy value, you will automatically attempt to flee.
You will only flee if your character is not in a wait state — i.e. has not
been using combat commands like weave, trip and bash, and has not been
tripped or bashed by an enemy.

WIMPY with no argument sets your wimpy value to 20% of your maximum hit points.

Some monsters are wimpy and will flee from you mid-fight.